Various observational studies and one clinical trial in a nutritionally deprived population have suggested that persons who use nutritional supplements or who have better nutritional status are at decreased risk of cataract. The Italian-American Collaborative Clinical Trial of Nutritional Supplements and Age-Related Cataract is an 8 year study whose major objective is to evaluate the safety and efficacy of a vitamin/mineral supplement at dosages near the recommended daily allowance in preventing age-related cataract or delaying its progression. As secondary objectives, data will be collected on incidence and progression rates, and risk factors for the disease. To this purpose a cohort of 1200 patients with very early or no cataract will be randomized to a broad spectrum multivitamin/mineral supplement or matching placebo. Lens status will be assessed by taking and grading lens photographs at the baseline examination and at yearly intervals for at least five years of follow-up. The study will be done in three phases. Phase I (6 months) will involve development of a Manual of Procedures, hiring and training of personnel necessary for data collection, identification of patient referral sources, preparation of data collection forms, preparation of data management procedures and pilot testing of all procedures and forms. In Phase II (6 1/2 years), 1200 participants will be enrolled into the study, interviewed, examined and randomized to an intervention. Patients will then be reexamined at 6 month intervals. Phase III (10 months) will involve data quality control procedures and preparation of manuscripts.